A battery is made up of a group of battery cells (referred to as cells). The cells are grouped together in series or in parallel or a combination of both to provide the current and voltage specifications needed to create the battery. The performance of the battery depends on the performance of these cells.
Due to the current manufacturing technology and process, cells from the same assembly line, produced one after another, will not have the exact same specifications or performance. There will always be minor differences. When cells are grouped together, the performance is limited by the weakest cell. The performance of the cells will also deteriorates with age, since the worst cell in a battery deteriorates from a lower starting point than the other cells, it renders the battery obsolete as soon as one cell is near the end of its functional life.
When a battery is being charged, all cells are receiving electrical current and charging at the same time. As soon as one cell has reached its maximum capacity, the charging process will stop for all cells. This happens regardless of the status of the other cells. After a battery is charged, each individual cell is at different capacities from one another. As cells age, the lowest performance cell dominants the performance, the capacity will decrease, resulting in a significant decrease in its capacity to hold a charge.
When a battery is discharging, all cells are discharging at the same time. As soon as one cell is depleted, discharging will stop no matter the capacity of the other cells. This causes a battery to be non-functional even if other cells are still at full or still capable of discharging. A fully charged battery will indicate full charge when tested, that is because the measurement is performed across all cells, within the cells there could be bad cells at lower capacity. With age, the cell performance will decrease and the battery will need to be charged more often and hold less charge.
It would be desirable to have an intelligent battery optimization, equalization management system capable of monitoring all battery cells within a battery, ensuring balanced charge/discharge of each cell and performing equalization of charges between all the cells. It would be also desirable to apply such an intelligent battery optimization, equalization management system in various fields such as but not limited to electric vehicle charging.